The KV-1s is the more mobile version of the KV and it's heavier-armored cousin, the KV-3. While it lacks much armor and has weak guns (except for the 122 D-2-5T), it does have decent mobility and tends to play more as a medium tank than a heavy. For this reason, the kv-1s is not a popular choice, since players expect decent survivability in head-to-head engagements in the heavy tank class. But, the KV-1s offers invaluable practice in learning to drive and operate the IS tank series, as the rest of the USSR heavy tank line is fairly mobile. Research along this tree unlocks the Tier 7 heavy tank, IS.

Historical Info

In response to criticisms about the slow KV-1 tank, the lighter and modernized KV-1S heavy tank was released, with thinner armour and a smaller, lower turret in order to reclaim some speed. Importantly, the KV-1S also had a commander's cupola with all-around vision blocks, for the first time for a Soviet heavy tank. However, the thinning-out of the armor called into question why the tank was being produced at all, when the T-34 could seemingly do everything the KV could do and much more cheaply. The Soviet heavy tank program was close to cancellation in mid-1943.
Total of 1,370 vehicles of the series were produced.